There are two guitars playing. The one that is in standard tuning can still be heard by your ears - the strings on the guitar are vibrating in standard tuning. The other guitar you are hearing is the virtual one that has been dropped down a half step.

You need to turn up the volume of the modeled sound (your amp / monitors) so that you can no longer hear the natural string acoustic vibrations. Or you can wear headphones.

To test this, try recording a bit of your playing. You won't hear the standard tuning on playback - only the modeled (alternate tuning) sound is recorded.

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Life is what happens to you while you're busy making other plans..... John Lennon